Thermal Energy Flashcards
What is conduction
The transfer of thermal energy through a substance without the substance itself moving
What are the three ways in which thermal energy is transferred
Conduction
Convection
Thermal Radiation
Why does conduction take plae faster in metals
Because metals have free electrons tht an move easily through the structure if the metal and speed up the transfer of energy
What is convection
The transfer of heat through fluids (gases and liquids) through the upward movement of warmer less dense regions of fluid
What is a convection current
A circulating current where a liquid is heated at the bottom and that region becomes hotter, the heated water expands and becomes less dense so it rises up above the colder less dense regions of water which are then heated . The heated water then cools at the top and becomes more dense so sinks back down again, creating a cycle .
In what substances does convection occur
Fluids
ie liquids and gases
What is thermal radiation
The transfer of energy by infra red waves
Which is the fastest form of transfer of thermal energy
Thermal radiation
How do we receive heat form the sun
Through IR radiation because it travels at the speed of light in a vacuum
What colours are good absorbers / poor reflectors of IR radiation
Matt black and dark surfaces
What is a good reflector and port absorber of IR RADIATION
Highly shiny grey
